Buggy code:
public class JettyHttpClient implements com . proofpoint . http . client . HttpClient { private static final String [ ] DISABLED_CIPHERS = new String [ ] { "TLS_ECDHE_ECDSA_WITH_RC4_128_SHA" , "TLS_ECDHE_RSA_WITH_RC4_128_SHA" , "SSL_RSA_WITH_RC4_128_SHA" , "TLS_ECDH_ECDSA_WITH_RC4_128_SHA" , "TLS_ECDH_RSA_WITH_RC4_128_SHA" , "SSL_RSA_WITH_RC4_128_MD5" , "TLS_DHE_RSA_WITH_AES_256_CBC_SHA256" , "TLS_DHE_DSS_WITH_AES_256_CBC_SHA256" , "TLS_DHE_RSA_WITH_AES_256_CBC_SHA" , "TLS_DHE_DSS_WITH_AES_256_CBC_SHA" , "TLS_DHE_RSA_WITH_AES_128_CBC_SHA256" , "TLS_DHE_DSS_WITH_AES_128_CBC_SHA256" , "TLS_DHE_RSA_WITH_AES_128_CBC_SHA" , "TLS_DHE_DSS_WITH_AES_128_CBC_SHA" , "TLS_DHE_RSA_WITH_AES_256_GCM_SHA384" , "TLS_DHE_DSS_WITH_AES_256_GCM_SHA384" , "TLS_DHE_RSA_WITH_AES_128_GCM_SHA256" , "TLS_DHE_DSS_WITH_AES_128_GCM_SHA256" , "SSL_DHE_RSA_WITH_3DES_EDE_CBC_SHA" , "SSL_DHE_DSS_WITH_3DES_EDE_CBC_SHA" } ; private static final AtomicLong nameCounter = new AtomicLong ( ) ; private static final String PLATFORM_STATS_KEY = "platform_stats" ; private final HttpClient httpClient ; private final long maxContentLength ; private final Long requestTimeoutMillis ; private final long idleTimeoutMillis ; private final RequestStats stats = new RequestStats ( ) ; private final JettyHttpClient . CachedDistribution queuedRequestsPerDestination ; private final JettyHttpClient . CachedDistribution activeConnectionsPerDestination ; private final JettyHttpClient . CachedDistribution idleConnectionsPerDestination ; private final JettyHttpClient . CachedDistribution currentQueuedTime ; private final JettyHttpClient . CachedDistribution currentRequestTime ; private final JettyHttpClient . CachedDistribution currentRequestSendTime ; private final JettyHttpClient . CachedDistribution currentResponseWaitTime ; private final JettyHttpClient . CachedDistribution currentResponseProcessTime ; private final List < HttpRequestFilter > requestFilters ; private final Exception creationLocation = new Exception ( ) ; private final String name ; public JettyHttpClient ( ) { } public JettyHttpClient ( HttpClientConfig config ) { } public JettyHttpClient ( HttpClientConfig config , Iterable < ? extends HttpRequestFilter > requestFilters ) { } public JettyHttpClient ( HttpClientConfig config , JettyIoPool jettyIoPool , Iterable < ? extends HttpRequestFilter > requestFilters ) { } private JettyHttpClient ( HttpClientConfig config , Optional < JettyIoPool > jettyIoPool , Iterable < ? extends HttpRequestFilter > requestFilters ) { } @ Override public < T , E extends Exception > T execute ( Request request , ResponseHandler < T , E > responseHandler ) throws E { } @ Override public < T , E extends Exception > HttpResponseFuture < T > executeAsync ( Request request , ResponseHandler < T , E > responseHandler ) { } private Request applyRequestFilters ( Request request ) { } private HttpRequest buildJettyRequest ( Request finalRequest , AtomicLong bytesWritten ) { } public List < HttpRequestFilter > getRequestFilters ( ) { } @ Override @ Managed @ Flatten public RequestStats getStats ( ) { } @ Managed @ Nested public JettyHttpClient . CachedDistribution getActiveConnectionsPerDestination ( ) { } @ Managed @ Nested public JettyHttpClient . CachedDistribution getIdleConnectionsPerDestination ( ) { } @ Managed @ Nested public JettyHttpClient . CachedDistribution getQueuedRequestsPerDestination ( ) { } @ Managed @ Nested public JettyHttpClient . CachedDistribution getCurrentQueuedTime ( ) { } @ Managed @ Nested public JettyHttpClient . CachedDistribution getCurrentRequestTime ( ) { } @ Managed @ Nested public JettyHttpClient . CachedDistribution getCurrentRequestSendTime ( ) { } @ Managed @ Nested public JettyHttpClient . CachedDistribution getCurrentResponseWaitTime ( ) { } @ Managed @ Nested public JettyHttpClient . CachedDistribution getCurrentResponseProcessTime ( ) { } @ Managed public String dump ( ) { } @ Managed public void dumpStdErr ( ) { } @ Managed public String dumpAllDestinations ( ) { <START_BUG> return ( String . format ( "%s\t%s\t%s\t%s\t%s\n" , "URI" , "queued" , "request" , "wait" , "response" ) ) + ( httpClient . getDestinations ( ) . stream ( ) . map ( JettyHttpClient :: dumpDestination ) . collect ( Collectors . joining ( "\n" ) ) ) ; <END_BUG> } @ SuppressWarnings ( "UnusedDeclaration" ) public String dumpDestination ( URI uri ) { } private static String dumpDestination ( Destination destination ) { } private static List < JettyHttpClient . JettyRequestListener > getRequestListenersForDestination ( Destination destination ) { } private static List < org . eclipse . jetty . client . api . Request > getRequestForDestination ( Destination destination ) { } private static String dumpRequest ( long now , JettyHttpClient . JettyRequestListener listener ) { } private static double nanosToMillis ( long nanos ) { } @ Override public void close ( ) { } @ Override public String toString ( ) { } @ SuppressWarnings ( "UnusedDeclaration" ) public StackTraceElement [ ] getCreationLocation ( ) { } private static class JettyResponse implements com . proofpoint . http . client . Response { private final Response response ; private final CountingInputStream inputStream ; JettyResponse ( Response response , InputStream inputStream ) { } @ Override public int getStatusCode ( ) { } @ Override public String getStatusMessage ( ) { } @ Override public String getHeader ( String name ) { } @ Override public ListMultimap < String , String > getHeaders ( ) { } @ Override public long getBytesRead ( ) { } @ Override public InputStream getInputStream ( ) { } @ Override public String toString ( ) { } } private static class JettyResponseFuture < T , E extends Exception > extends AbstractFuture < T > implements HttpResponseFuture < T > { public enum JettyAsyncHttpState { WAITING_FOR_CONNECTION , SENDING_REQUEST , WAITING_FOR_RESPONSE , PROCESSING_RESPONSE , DONE , FAILED , CANCELED ; } private static final Logger log = Logger . get ( JettyHttpClient . JettyResponseFuture . class ) ; private final long requestStart = System . nanoTime ( ) ; private final AtomicReference < JettyHttpClient . JettyResponseFuture . JettyAsyncHttpState > state = new AtomicReference < > ( JettyHttpClient . JettyResponseFuture . JettyAsyncHttpState . WAITING_FOR_CONNECTION ) ; private final Request request ; private final Request jettyRequest ; private final ResponseHandler < T , E > responseHandler ; private final AtomicLong bytesWritten ; private final RequestStats stats ; private final String traceToken ; JettyResponseFuture ( Request request , org . eclipse . jetty . client . api . Request jettyRequest , ResponseHandler < T , E > responseHandler , AtomicLong bytesWritten , RequestStats stats ) { } @ Override public String getState ( ) { } @ Override public boolean cancel ( boolean mayInterruptIfRunning ) { } protected void completed ( Response response , InputStream content ) { } private T processResponse ( Response response , InputStream content ) throws E { } protected void failed ( Throwable throwable ) { }

Fix:
return ( String . format ( "%s\t%s\t%s\t%s\t%s%n" , "URI" , "queued" , "request" , "wait" , "response" ) ) + ( httpClient . getDestinations ( ) . stream ( ) . map ( JettyHttpClient :: dumpDestination ) . collect ( Collectors . joining ( "\n" ) ) ) ;